04 Prius wont start

try a jump start, jump pack, battery charger or new 12v.

 

Its the hybrid battery.

 

There’s many different paths for the hybrid battery. Your not alone there all failing because people stopped driving there cars andan old battery will self deplete. I assume it’s the original battery which tells me the car was driven a lot till suddenly it’s not. That’s hard on the battery modules and Some modules have probably failed so I doubt a charge will fix this long term.
At that age the battery needs to be replaced anyway.

Like many posters you are asking a global question and not giving any info so we can advise.

How long have you owned the car
How many miles
White state do you live in
What is your diy level worked on cars all your life and understand and own lots of tools and a good DVM?
Know what an obd code reader is
Have strong electronic skills.
How much money do you want to spend.

A new battery is $1600 you install.
Alternatives are much cheaper and much more work and time and not so much a greater degree of long time success.

 

your next step is to measure the 12v under the hood. if it and the connections are good, should read above 12.6v.
after that, you need to have the trouble codes read at a dealer, or qualified hybrid shop with tech stream software.

 

If you don't mind sharing, who did that service for you?